Prime Minister Kevin Rudd is considering changes to Labor's carbon tax and asylum seeker policies, but the makeup of his ministry remains a mystery.

The new Treasurer, Chris Bowen, says the Labor leadership changes have already made a difference.

"This election is close and competitive again, and if the Liberal Party were measuring up the curtains and checking out the lounge suites in the ministerial offices and taking things for granted, there's a tight election now," he said.

"The Australian people have a really tough and close election now on their hands and we will be fighting for it very, very hard."

But with seven ministers departing the front bench, Opposition Leader Tony Abbott says the Government will not have enough experience to be credible.

"They're about to have the fifth reshuffle in just three years," he said.

rudd key points

Key points

Former ministers Kim Carr, Simon Crean tipped to return to Cabinet, along with other key Rudd supporters

New ministers will be sworn in on Monday, provided the Governor-General is available, before the first Cabinet meeting of the new Rudd Government

Ministers will have to help Mr Rudd decide when to have the election – with August 24 firming as the new date

Rudd Government will seek to shift debate on climate change and asylum seekers

Mr Abbott says the majority of his front bench were successful ministers in the Howard government.

"We have been a rock of stability and constancy for the last three years," he said.

Mr Rudd, who says his frontbench line-up will be revealed on Monday, is expected to reward his supporters, but so far has only named his Deputy, Anthony Albanese, and Treasurer.

Former ministers Kim Carr and Simon Crean are tipped to be promoted to the ministry, along with other key Rudd backers.

Mr Rudd has also announced the Government will be extending the deadline for agreement with the states and territories on the Gonski school education changes.

Carbon price on agenda for new Cabinet

The ABC understands they will discuss carbon pricing and the key question of whether the Government should move to a floating price sooner than 2015.

Labor frontbencher Jason Clare has told Channel Nine the Government wants to move to a flexible carbon price as soon as possible.

"The Government has always supported an emissions trading scheme. We tried to do that in the last Parliament, but the Liberals, the Greens stopped us doing that," he said.

"That's why Julia Gillard put in the carbon tax. We want an emissions trading scheme - we want to move to that as quick as we can.""

But Greens leader Christine Milne says she does not think people trust Mr Rudd on climate policy.

"He has back-flipped on climate so much that I don't think people would really trust him to actually respond to the science and to be rigorous about climate change," she said.

And with no sign of a slow-down in the number of asylum seeker boats trying to reach Australia, that too will be one of Cabinet's key priorities.

August 24 firming as new election date

Ministers will also have to help Mr Rudd decide on an election date, with August 24 firming as an early favourite.

"We'll wait and see. We'll have a discussion with the Cabinet," Mr Albanese said.

"It's not like there's a whole lot of options in terms of when the day could be."

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Chris Bowen gives first interview as Federal Treasurer

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Mr Albanese says unlike Julia Gillard's strategy, they will reserve the right to surprise.

Mr Bowen says the Prime Minister has concerns with the September 14 date proposed by his predecessor as it coincides with the Jewish day of Yom Kippur.

"There are Australians of the Jewish faith who would have great difficulty with an election on that date, and that is a factor that he's indicated very clearly that we will be taking into consideration," Mr Bowen said.

"But the important principle he's underlined is he believes in the traditional constitutional convention, that the Prime Minister goes to see the Governor-General, recommends a date and then announces it."

Senators debated and passed legislation to define charities and their governance, change private health insurance loadings and amend the Fair Work laws.

The Senate will sit again today in order to pass the main budget appropriation bills and the Government's tougher approach to the use of 457 visas for skilled migrants.

There will not be amendments, but it is understood the Government will try to soften business anger by reviewing the way the 457 changes will be put in place.